Tiny DNA tweezers can catch and release objects on-demand

October 29, 2008 -- Researchers in China are reporting development of a
new DNA “tweezers” that are the first of their kind capable of grasping and
releasing objects on-demand. The microscopic tweezers could have several
potential uses, the researchers note. Those include microsurgery, drug and gene
delivery for gene therapy, and in the manufacturing of nano-sized circuits for
futuristic electronics. Their study is scheduled for the November 12 issue of
the weekly Journal of the American Chemical
Society.

Zhaoxiang Deng and colleagues note
that other scientists have developed tweezers made of DNA, the double helix
molecule and chemical blueprint of life. Those tweezers can open and close by
responding to complementary chemical components found in DNA’s backbone.
However, getting the tweezers to grasp and release objects like real tweezers
has remained a bioengineering challenge until now.

The scientists describe
development of a pair of DNA tweezers composed of four DNA strands — three which
act as the “arms.” In laboratory studies, the scientists showed that they could
grab a piece of target DNA in the arms of the tweezers and release it on-demand
using a controlled series of hydrogen bonding and pH changes. The scientists
used fluorescent gel imaging to confirm the effectiveness of the tweezers’
operation.